For the second weekend in a row, observers are predicting a major government offensive against rebels in Syria's largest city, Aleppo. Fierce fighting has also been reported in parts of the capital, Damascus. Allegations of atrocities on both sides of the conflict have prompted a crescendo of criticism from the outside world.

Both sides claim to have gained the upper hand in the fighting over Aleppo, the country's commercial hub and the main city in the north. The government said last week that it had killed many rebels in Aleppo and would soon restore peace to the city.

But Mohammed Saeed, a spokesman for the Syrian Revolution General Commission, disagrees. He says that in recent days, Free Syrian Army — or FSA — fighters have taken roughly half of the city's territory and are pushing from the outer suburbs toward the city's center.

"FSA now is stronger than government army. In the last week, FSA was controlling maybe 10 percent of Aleppo, and now [it] is controlling 50 percent," he says. "Maybe [in] two days or three days, you will see FSA in the center of Aleppo."

Activists say a steady stream of defections is weakening the Syrian army. An activist in the central Syrian city of Tadmor who goes by the nom de guerre Majd al-Tadmori says that enraged authorities are combing the city and killing any defectors they find. Tadmor, also known as Palmyra, is home to many famous Hellenistic and Roman ruins.

"Sometimes they chase defectors through the ruins, near the Baal Temple or the Triumphal Arch," he says. "These ruins shouldn't even have cars driving near them, and the roads there have been closed. But now tanks and heavy vehicles are driving through the area."

On Friday, a jihadist rebel group called Al-Nusra Front claimed responsibility for the execution of a TV news anchor for Syrian state television, whom the group accused of being an apologist for the shabiha, or pro-regime militia.

The Free Syrian Army has responded to growing criticism of such atrocities. A video recently posted on YouTube purports to show Abdul Razzaq Tlass, an officer with the Free Syrian Army's Farouq Brigade. He pledges that the FSA will abide by the Geneva Convention and allow visits by the International Red Cross.

"We are revolting against a barbaric regime that has always tortured and treated detainees in brutal ways that led to the death of many people," he says in the video. "That's why we can never adopt the behavior of the very entity that we are revolting against."

On Friday, United Nations Secretary-General Ban Ki-moon noted that observers had predicted the current violence and humanitarian crisis in Syria nearly a year and half ago, when anti-government protests began. He blasted the U.N. for its failure to act.

"The next step was also forewarned: a proxy war with regional and international players arming one side or the other," he said. "All of these dire predictions have come to pass."

Following Ban's speech, the U.N. General Assembly overwhelmingly passed a resolution condemning the Syrian government's repression. Syria's ambassador to the U.N. dismissed the measure as a "piece of theater."

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Transcript

SUSAN STAMBERG, HOST:

This is WEEKEND EDITION from NPR News. I'm Susan Stamberg. For the second weekend in a row, observers are predicting a major government offensive against rebels in Syria's largest city, Aleppo. Fierce fighting has also been reported in parts of the capital, Damascus. NPR's Anthony Kuhn reports from Beirut that allegations of atrocities on both sides of the conflict have prompted a crescendo of criticism from the outside world.

ANTHONY KUHN, BYLINE: Both sides claim to have gained the upper hand in the fighting over Aleppo, the country's commercial hub and the main city in the north. The government said last week that it had killed many rebels in Aleppo and would soon restore peace to the city. But Mohammed Saeed, a spokesman for the Syrian Revolution General Commission, disagrees.

He says that in recent days, Free Syrian Army, or FSA, fighters have taken roughly half of the city's territory and are pushing from the outer suburbs toward the city's center.

MOHAMMED SAEED: FSA now is stronger than government army. In the last week, FSA was controlling maybe 10 percent of Aleppo, and now is controlling 50 percent. Maybe two days or three days, you will see FSA in the center of Aleppo.

KUHN: Activists say a steady stream of defections is weakening the Syrian army. Majd al-Tadmori is the nom de guerre of an activist in Tadmor in central Syria. He says that enraged authorities are combing the city and killing any defectors they find. Tadmor, also known as Palmyra, is home to many famous Hellenistic and Roman ruins.

MAJD AL-TADMORI: (Foreign language spoken)

KUHN: Sometimes they chase defectors through the ruins, he says, near the Baal Temple or the Triumphal Arch. These ruins shouldn't even have cars driving near them, and the roads there have been closed. But now tanks and heavy vehicles are driving through the area. On Friday, a jihadist rebel group called the Al-Nusra Front claimed responsibility for the execution of Mohammed al-Saeed, a TV news anchor for Syrian state television, whom the front accused of being an apologist for the Shabiha, or pro-regime militia.

The Free Syrian Army has responded to growing criticism of such atrocities. A video recently posted to YouTube purports to show Abdul Razzaq Tlass, an officer with the Free Syrian Army's Farouq Brigade. He pledges that the FSA will abide by the Geneva Convention and allow visits by the International Red Cross.

ABDUL RAZZAQ TLASS: (Through Translator) We are revolting against a barbaric regime that has always tortured and treated detainees in brutal ways that led to the death of many people. That's why we can never adopt the behavior of the very entity that we are revolting against.

KUHN: On Friday, U.N. General Secretary Ban Ki-moon, noted that observers had predicted the current violence and humanitarian crisis in Syria nearly a year and half ago when anti-government protests began. He blasted the U.N. for its failure to act.

BAN KI-MOON: The next step was also forewarned, a proxy war with regional and international players arming one side or the other. All of these dire predictions have come to pass.